Your alternator is one of the hardest working parts on your vehicle. It’s a common misconception that the battery in your vehicle is what supplies your power while the vehicle is running. The alternator not only supplies power to all of your vehicle’s electrical components while the vehicle is running, it’s also recharging your car battery at the same time. Every time you use your headlights, radio, GPS, air conditioner, heater, defroster, power seats, turn signal, dome lights, or power outlets, your alternator is making it all work by turning mechanical energy into electrical energy. Needless to say, when it dies, your car can’t function. That makes its replacement a pretty big priority. To keep you prepared for potential alternator failure (an increasing possibility as a vehicle ages), here’s a look at what it costs to replace one of these miniature power plants.

How Long Do Alternators Last?

It’s difficult to predict how long your alternator will last because many factors affect the life of an alternator. These factors include how the car is driven, the climate where it’s driven, and the electrical equipment it regularly operates. If you plan on keeping your car for longer than a few years, you can expect to replace your alternator. Alternators typically last between 40,000 to 100,000 miles. 

Signs of a Bad Alternator

Here are some warning signs that you need a new alternator .
  • Noises from the engine: if an alternator is not able to spin properly, the engine will squeal or make other unusual noises. 
  • Car stalls or has difficulty starting: While starting the car is the main function of the battery, if the alternator is failing, the battery won’t charge. A dead battery is a potential sign of a bad alternator.
  • Dimmed headlights: Your headlights may appear dimmer due to inadequate power from a failing alternator.
  • Illuminated dashboard warning lights: These can include the battery light, ALT, or ‘check engine lights
  • Malfunctioning Electrical System: Because the alternator provides electrical power to the vehicle, you’ll notice some electrical issues in the event of a failing alternator. This could include power windows and mirrors, radio, air conditioner, or any other electrical components.

So How Much Should an Alternator Replacement Cost?

The average time for an alternator replacement is two-to-three hours. That gives you roughly $120- $200 in labor to start. The remaining cost is going to depend on the price of your alternator. Most alternators can be purchased from auto parts stores for much less than an original equipment manufactured (OEM) replacement through the dealership, but the buyer must beware here. Certain discount auto parts stores carry electrical parts that have lower quality than the original equipment on a new car. Buying an alternator aftermarket is not inadvisable, a lot of money can be saved that way; but, make sure you’re using a quality part. Purchasing a new alternator from the same company that made the original version (OEM) is a smarter purchase decision. Alternators can average anywhere from $100 to $350 depending on make and model. Most vehicles will have an average cost between $350-400 for the total job of an alternator replacement if no other parts need to be replaced. If the serpentine belt is included in the process, add another $20 to $50 to your bill. If you decide to go with dealership parts and labor, expect the bill to climb over $500 in many cases. Because the total cost depends on the vehicle, you can expect to pay anywhere between $350 - $900 for an alternator replacement.

Do You Have to Replace the Battery When Replacing the Alternator? 

Your alternator is run by your serpentine belt . On nearly all late-model vehicles a serpentine belt , or drive belt , is used to drive the main pulleys , and this must be removed in order to remove the alternator. If the belt hasn’t been replaced in some time, or is showing signs of cracking or wear, now is the perfect time to replace it. It will already be part of the labor to remove the alternator, so the only added cost is the price of the belt. In rare instances, the wiring harness plug that plugs into your alternator is also replaced. This is only the case when excessive heat has caused the plastic plug to deteriorate or even melt. The last item which may require replacement, along with your alternator, is your battery. Starting your vehicle takes pulls a lot of energy from your battery. If the alternator wasn’t recharging it constantly, it would only last for a couple of starts. If your alternator fails , your vehicle will still need power to operate. It will find this power in your battery. Unfortunately, without your alternator working to recharge it, this could do some damage to your battery’s cells. Sometimes you get lucky and the battery survives the strain. The technician usually finds that out with a quick test before the work even begins.

Alternator Repair Cost

In some instances, your faulty alternator might require minor repairs instead of a full replacement. You may need a new belt or to clean the electrical connecting points. In this case, you’ll have to pay for labor costs and a diagnostic fee, which will cost you a few hundred dollars depending on your vehicle. Some vehicles offer alternator repair kits, which can be found at a local auto parts store . In general, a full alternator replacement is usually the better option versus attempting a repair.

Can I Save Money with a Used Alternator?

This is one of the most inadvisable things to do. When it comes to the parts of your car’s electrical system , you truly do get what you pay for. Any used electrical part is going to be a gamble, and will probably not include a warranty . This is also true for rebuilt alternators . Keep in mind that rebuilt and remanufactured are two different things. A rebuilt alternator is an alternator that has failed and then had the internal parts which failed replaced; everything else inside it stays. A remanufactured alternator is usually all new internal parts surrounded by a used casing. Everything gets replaced inside, no matter what failed. If you need to save a few bucks, go with remanufactured over brand new, but steer clear of rebuilt and used.

Bottom Line:

The alternator is a critical part of your vehicle that serves many important functions. Understanding the warning signs of a failing alternator and how much you can expect to pay for a new one can prepare you for when you need to replace the alternator on your vehicle. 

(These repair prices can also fluctuate based on geographic location, as well as vehicle make and model; these numbers represent averages, not actual prices offered at any specific auto repair shop.)

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